Much of the nation's infrastructure is buried, including underground storage tanks, pipelines, power cables, and communication lines. The locations of these are not usually marked on the surface and are subject to excavation damage if a construction crew is not aware of their exact locations or if an operator is careless. For example, an extensive network of critical pipeline infrastructure delivers gas and oil throughout the United States. Recent natural gas and petroleum industry incidents have drawn renewed attention to the topic of pipeline safety. While construction crews are required to call and verify locations of utility lines before commencing excavation, not all do. Although utility and pipeline markers as well as pipeline maps are available and in use, excavation damage to pipelines still occurs [Haurwitz, R. K. M, Nesmith, J., Abilene Blast Shows Deadly Holes In Call-First Excavation Law, The Statesman, 2001 Jul. 24.]. Given the high risks to people, property, and the environment, systems that can prevent excavation damage to pipelines are needed.
The federal Pipeline and Hazardous Materials Safety Administration (PHMSA) monitors damage from pipeline incidents, and coordinates communication about and response to pipeline incidents [Hall, S. PHMSA's Damage Prevention Assistance Program: Strengthening State Damage Prevention Programs, Ohio Gas Association]. The Pipeline Inspection, Protection, Enforcement and Safety Act of 2006 calls for the development of enhanced measures and technologies to increase safety in pipeline transportation [Global Legal Information Network] Pipeline Inspection, Protection, Enforcement, and Safety Act of 2006. Washington (DC): While laws mandating pipeline safety exist, the specific applications and safety requirements vary from state to state [see e.g., Alabama 811 (Alabama One Call). One Call Laws Summary/State One Call Laws and Provisions. Fultondale (AL): AOC]. For this reason, excavation damage prevention is implemented at the state and local level [Hall, S. PHMSA's Damage Prevention Assistance Program: Strengthening State Damage Prevention Programs. Ohio Gas Association. In: CGA Excavation Safety Conference presentations, 2009 Feb. 17; Orlando, Fla.].
Several types of systems already exist (discussed below in Prior Art) that are designed to alert the pipeline companies of potential excavation damage. However, by the time the pipe-line company is notified and personnel are dispatched to alert the construction crew, the damage has already occurred in most cases. Fewer systems exist for alerting the construction crew itself conducting the excavation. Furthermore, many of these systems are best suited for new construction and are not applicable for existing pipelines. Many also require high maintenance or operation costs. The present invention would warn construction crews that they are near a pipeline or any other buried infrastructure with the use of devices that contain environmentally safe, brightly colored odoriferous gas that when released will make a loud audible sound. If the excavation crew is not aware that it is near pipelines, these devices would alert them to their presence.
As of 2003, there are more than two million miles of natural gas and petroleum transmission and distribution pipelines in the U.S. [Pipeline and Hazardous Materials Safety Administration General Pipeline FAQs: How big is our pipeline infrastructure: how many miles of what kinds of pipelines are there in the United States? Washington (DC): PHMSA]. According to PHMSA, the annual cost of significant pipeline incidents between 1991 and 2010 ranged from tens of millions of dollars to greater than 1 billion dollars [Significant Pipeline Incidents. Washington (DC): PHMSA]. (Between 1997 and 2001, property damage from natural gas pipelines in the US ranged from at least $10M to $45M, and property damage from petroleum pipelines ranged from at least $30M to $190M [Pion, C. A, DiPalma, F. T. Pipeline Integrity Management Enhanced Safety, in: National Safety Council conference presentations, 90th Annual Congress and Expo, 2002 Oct. 7; San Diego, Calif., p. 15]). Historically, of the damage to natural gas pipelines, approximately 35% is due to damage from excavation [C-Fer Technologies, Risk and Reliability Analysis for Pipelines, in: CO2 Capture and Storage Workshop presentations, 2006 Jan. 27; Calgary, Alberta, p. 8].
Similar hazards and costs exist for buried power cables; electrocutions and explosions can occur if these cables are cut. Underground storage tanks (USTs) can contaminate ground water or release toxic chemicals into the atmosphere if breached during an excavation. Buried communication lines may be less hazardous, but costs of disruption of communication are significant and growing.
There are many potential applications for excavation detection system technology, from installation during new pipelines as well as retrofitting existing pipelines in High Consequence Areas (HCAs). HCAs are areas where a release of natural gas or petroleum would cause significant damage to people, property or the environment [National Pipeline Mapping System (Pipeline and Hazardous Materials Safety Administration) [Internet]. Data Dissemination. Washington (DC): NPMS (PHMSA)]. Many potential customers exist in the local, regional, national, and international pipeline companies that provide natural gas and petroleum transport in the United States New pipelines planned in the US range from small projects [Pipelines International: New Pipeline Projects to Bring Gas Down South in US. Houston (Tex.): Pipelines International, 2010 Nov. 9] to larger projects involving hundreds to thousands of miles of new pipeline [Pipeline and Gas Journal ONEOK Partners to Build New Gulf Coast Natural Gas Liquids Pipeline. Pipeline and Gas Journal. 2001 May; 238(5).].